RhinoPower Ltd

TechSupport · Guru

H8/532 Adapter

Metalfab_101 · Member

Fair enough, if the processor has to come off either way then I guess the best choice is the EPROM version of the processor. But where to source them?

Oh, and if it's too difficult/expensive to get the EPROM version is the daughterboard something that will need to be custom made?

TechSupport · Guru

The daughterboard involves desoldering the processor and fitting a plug to take a daughterboard that has the original processor, an EPROM and a port expander IC.
The daughterboard option is usually used when an EPROM IC isn't available.
Desoldering the processor is pretty simple, mask off the rest of the PCB and hit it with a hot air gun. You can get special adapters for hot air guns but they're not really necessary. You can also get some stuff called chipquick (sp?) that lowers the melting temperature of the solder.

Metalfab_101 · Member

Rhinoman wrote:
Apparently there was an EPROM version of this processor, used for development testing. May be a bit tricky to get hold of but would make reprogramming these ECUs a lot easier. Alternatively a daughterboard could be used with an external EPROM or Flash chip.

I've been thinking about this, and i get the feeling these eprom versions of the processor arent going to be easy to come by. Add to that the cost, and complication of desoldering and resoldering a socket and the daughterboard option starts looking like an option.

How difficult do you think installing the daughterboard would be? In my mind i had something like the 10 pin header you added to your baleno ecu.

Metalfab_101 · Member

Very interesting rhinoman, this is something i'd be keen to look into further.

TechSupport · Guru

Apparently there was an EPROM version of this processor, used for development testing. May be a bit tricky to get hold of but would make reprogramming these ECUs a lot easier. Alternatively a daughterboard could be used with an external EPROM or Flash chip.

TechSupport · Guru

These are an older generation chip which can only be programmed off the board. There are two different types, Masked ROM which cannot be changed and One Time Programmable (OTP), despite the name OTP chips can be reprogrammed but they can not be erased so you can only change '1's to '0's. Now if your code is located in the top half of memory then you redirect the code by clearing bits and insert new code in the lower part of the memory.
Alternatively you can take an OTP chip and, very carefully, using fuming nitric acid you can remove the plastic casing from the top of the chip and create your own EPROM processor.
I only have masked ROM variants here at the moment, I'm going to see if I can read them using the same adapter.

Metalfab_101 · Member

Very interesting Rhinoman!

Do you think there is anyway to reprogram this type of ECU without removing the chip frmo the board? Like the way you mentioned you can do with the Baleno ECUs?

TechSupport · Guru

While looking for other stuff I came across an off the shelf programming adapter for the H8/532. This adapter will allow the processor to be read/written in a PROM programmer:

http://www.mcumall.com/comersus/store/comersus_viewItem.asp?idProduct=4353

The H8/532 was used in a large number of Suzuki ECUs during the mid-late 80s. I'd already designed an adapter can I can't get them made as cheaply as this so I've ordered one to try out. For those who don't know what an H8/532 looks like, her is the pic that Metalfab posted:

https://i7.photobucket.com/albums/y270/Metalfab_101/X-90%20ECU/27122009238.jpg